One of the biggest mortgage lenders in the U.S. said it would pay $1.75 billion to buy a well-known real-estate brokerage. The deal, once it goes through, could have major consequences for millions of home buyers.

Rocket Companies agreed to acquire Seattle-based Redfin in a $1.75 billion deal that will bring together the nation's largest mortgage

Rocket Cos. is pushing deeper into the property market with a deal to buy Redfin Corp. that values the real estate listing site at $1.75 billion.